For example, when copying an original image, digital copying machines that are presently introduced into the market as image-forming apparatuses read the original image by using an image-reading section, subject the original image that has just been read to a specified image processing by using an image-processing section, and then print the image information by using a recording section. Therefore, in the digital copying machine of this type, an image is copied onto a sheet of paper by using only the image-processing functions that are provided in the digital copying machine.
Here, in recent years, it has been proposed that a plurality of image-recording apparatuses and/or other apparatuses be organized into a network. For example, Japanese Laid-Open Patent Publication 53-116834/1978 Tokukoushou 53-116834) discloses an arrangement wherein a plurality of image-reading apparatuses and a plurality of image-recording apparatuses are connected through a control section. In such an arrangement, an original image that has been read by any of the image-reading apparatuses is printed by any of the image-recording apparatuses. This arrangement makes it possible to shorten the stand-by time of the image-reading apparatus that is caused by processes, such as an exchanging process of originals in the image-reading apparatuses.
Moreover, Japanese Laid-Open Patent Publication 61-198958/1986 (Tokukoushou 61-198958) discloses an image-forming system wherein a plurality of copying machines, each having an image-reading section and an image-recording section, are connected to a control device. In this image-forming system, according to an original document copying mode that has been set, an image signal that is to be recorded is supplied to the plurality of copying machines in a distributed manner, and copying operations are carried out by the copying machines in parallel with one another.
However, the conventional image-forming systems have the following problems.
For example, various image-processing functions in the digital copying machine are dependent upon software. Here, with the recent remarkable developments of the software, the image-processing functions have been highly improved in a very short period, and new copying machines having additional unprecedented functions have been newly introduced into the market. Consequently, for example, even when a digital copying machine having desired image-processing functions is purchased, the digital copying machine, which has the highest image-processing functions at the time of the purchase, will soon become out-dated with relatively low functions in a short period.
In this case, it is impossible for the purchased digital copying machine to obtain functions higher than those originally provided in the digital copying machine. In the case when higher functions or newer functions are required, it is inevitable that a new copying machine to replace the older one has to be purchased. This tends to impose a big burden on users on an economic basis, and also to present an inherent problem for makers that try to provide consumers with new merchandise.